An Israeli principal wanted on child sexual abuse charges in Australia has once again successfully claimed mental incompetence to Israeli authorities and will evade extradition hearings for another six months.

Key points:

Malka Leifer is wanted by Victoria Police on 74 charges of child sexual abuse, including indecent assault and rape, allegedly committed while she was the principal of the Adass Israel ultra-orthodox Jewish girls' school in Melbourne.

Last week, Ms Leifer convinced another psychiatrist review board in Israel that she was too unwell to face an extradition hearing.

Ms Leifer has avoided every single one of her extradition hearings in the last three years, claiming she suffers from panic attacks and anxiety.

Ms Leifer's victims were notified overnight by Israeli authorities of the devastating news.

"We've all had a week filled with anxiety, watching the clock and waiting to hear updates from Israel," former Adass student Dassi Erlich told the ABC in a statement.

"We are devastated, worried and wondering if we will ever have closure. It's really hard not to lose hope but we have no plans to give up the campaign to #bringleiferback. We are fighting for justice for ourselves, Malka Leifer's past and possibly future victims."

A Federal Government spokesperson told the ABC "the Government will continue to advocate for the extradition of Malka Leifer, so she finally faces justice in Australia".

Meanwhile, shadow attorney-general Mark Dreyfus said Labor would also continue to press for the extradition of Ms Leifer.

"While extradition requests are often complex and take some time to resolve, I and my colleagues are very concerned that justice is being delayed in this instance for reasons that are difficult to understand," he said.

"I am very grateful that Premier Daniel Andrews raised this issue directly with Prime Minister Netanyahu when he visited Israel in December last year.

"I also want to thank survivors of the alleged assaults, such as Dassi Erlich, who have shown great courage and integrity in their campaign to bring Ms Leifer to justice."